Hypertext

Hypertext
Hypertext, made famous by the
World Wide Web,
is most simply a way of
constructing documents that reference other documents.
Within a hypertext document, a block of text can be tagged as
a hypertext link pointing to another document.
When viewed with a hypertext browser, the link can be activated
to view the other document. Of course, if you're reading
this document, you're already familiar with the concept.

Hypertext's original idea was to take advantage of
electronic data processing to
organize large quantities of
information that would otherwise overwhelm a reader.
Two hundred years ago, the printing press
made possible a similar innovation - the encyclopedia.
Hypertext's older cousin combined topical articles with
an indexing system to afford the researcher one or perhaps
two orders of magnitude increase in the volume of accessible
information.
Early experience with hypertext suggests that it may ultimately
yield an additional order of magnitude increase, by
making directly accessible information that would otherwise
be relegated to a bibliography.
Hypertext's limiting factor appears not to be the physical
size of some books, but rather the ability of the reader
to navigate increasingly complex search structures.
Currently, additional increases in human information processing ability
seem tied to developing more sophisticated automated search tools,
though the present technology
presents possibilities that remain far from fully explored.

Augmenting basic hypertext with graphics, more complex user input fields
and dynamically generated documents adds considerable power and
flexibility to this concept.
Hypertext, though still useful
for its original goal of organizing large quantities of
information, becomes a simple, general purpose user interface that fits
neatly into the increasingly popular client-server model.
It does not seem difficult to image a day when restaurant orders,
for example,
will be taken using a hand-held hypertext terminal, relayed
directly to the kitchen for preparation, and simultaneously
logged to a database for later analysis by management.

Characteristics of good hypertext

The flexibility of hypertext gives free range to the author's creativity,
but good hypertext appears to have some common characteristics:

Lots of documents. Much of the hypertext's power comes
from its ability to make large quantities of information accessible.
If all the text in your system can be printed on ten pages, it
would be just as simple to read through it from beginning to end
and forget all this hypertext silliness. On the other hand, if there
are ten million pages of text in your system, then
someone could follows a link on atomic energy and ultimately
hope to find a description of the U-238 decay process.

Lots of links. If each document has just one link, then
it is little more than normal, sequential text. A hypertext document
should present the reader with several links, offering a choice about
where to go next. Ideally, a document should present as many relevant
links as the reader can easily comprehend and select among.

Range of detail. The great advantage of hypertext is that it
permits readers to explore to a breadth and depth that is simply not
feasible in print. To make this accessible, available hypertext documents
should range from the broadest possible overview
of a subject, down to its gritty details.
Imagine the Encyclopedia Britannica, all thirty-odd volumes of it,
searchable online and with each article possessing links to
a half dozen reference documents with even more detailed subject coverage.
This is the potential of hypertext.

Correct links. This may seem trivial, but it's amazing
how many Web links point nowhere. In general, be careful linking to any
hypertext document not under your direct control. Can you count on
it to be there later?

Guidelines for a hypertext reference system

Hypertext seems best suited for reference material, so here are my
suggested guidelines for creating hypertext reference systems, with the
Internet Encyclopedia offered as an example:

Reference documents. Start by assembling a good set of
core reference material. In the Encyclopedia's case, the RFCs that
document standard Internet protocols form this core. Ideally, the
reference core should consist of extremely detailed documents, offering
the highest possible degree of completeness. A general reference
work on physics might start with a large collection of scientific papers.

Topical articles. Augment the core reference material
with articles at a broader level of detail. Systematic organization
of these articles, perhaps using an outline as a framework, is
essential to making them accessible to the reader. The articles
should be focused, and short enough to be easily digestible
in one piece.

Search engine. A good search engine is invaluable for
any large collection of documents. The Internet Encyclopedia
uses a search model
based on searching outward from a particular page, in order
to facilitate both topical and keyword searches.

Extras. These can include graphics, audio and video clips,
problems and exercises, student courses, simulations, sample programs,
ordering forms, database tables, and revision histories, to name a few.